drivers/iio/inkern.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* The industrial I/O core in kernel channel mapping
   3  *
   4  * Copyright (c) 2011 Jonathan Cameron
   5  */
   6 #include <linux/err.h>
   7 #include <linux/export.h>
   8 #include <linux/slab.h>
   9 #include <linux/mutex.h>
  10 #include <linux/of.h>
  11
  12 #include <linux/iio/iio.h>
  13 #include "iio_core.h"
  14 #include <linux/iio/machine.h>
  15 #include <linux/iio/driver.h>
  16 #include <linux/iio/consumer.h>
  17
  18 struct iio_map_internal {
  19         struct iio_dev *indio_dev;
  20         struct iio_map *map;
  21         struct list_head l;
  22 };
  23
  24 static LIST_HEAD(iio_map_list);
  25 static DEFINE_MUTEX(iio_map_list_lock);
  26
  27 static int iio_map_array_unregister_locked(struct iio_dev *indio_dev)
  28 {
  29         int ret = -ENODEV;
  30         struct iio_map_internal *mapi, *next;
  31
  32         list_for_each_entry_safe(mapi, next, &iio_map_list, l) {
  33                 if (indio_dev == mapi->indio_dev) {
  34                         list_del(&mapi->l);
  35                         kfree(mapi);
  36                         ret = 0;
  37                 }
  38         }
  39         return ret;
  40 }
  41
  42 int iio_map_array_register(struct iio_dev *indio_dev, struct iio_map *maps)
  43 {
  44         int i = 0, ret = 0;
  45         struct iio_map_internal *mapi;
  46
  47         if (maps == NULL)
  48                 return 0;
  49
  50         mutex_lock(&iio_map_list_lock);
  51         while (maps[i].consumer_dev_name != NULL) {
  52                 mapi = kzalloc(sizeof(*mapi), GFP_KERNEL);
  53                 if (mapi == NULL) {
  54                         ret = -ENOMEM;
  55                         goto error_ret;
  56                 }
  57                 mapi->map = &maps[i];
  58                 mapi->indio_dev = indio_dev;
  59                 list_add_tail(&mapi->l, &iio_map_list);
  60                 i++;
  61         }
  62 error_ret:
  63         if (ret)
  64                 iio_map_array_unregister_locked(indio_dev);
  65         mutex_unlock(&iio_map_list_lock);
  66
  67         return ret;
  68 }
  69 EXPORT_SYMBOL_GPL(iio_map_array_register);
  70
  71
  72 /*
  73  * Remove all map entries associated with the given iio device
  74  */
  75 int iio_map_array_unregister(struct iio_dev *indio_dev)
  76 {
  77         int ret;
  78
  79         mutex_lock(&iio_map_list_lock);
  80         ret = iio_map_array_unregister_locked(indio_dev);
  81         mutex_unlock(&iio_map_list_lock);
  82
  83         return ret;
  84 }
  85 EXPORT_SYMBOL_GPL(iio_map_array_unregister);
  86
  87 static const struct iio_chan_spec
  88 *iio_chan_spec_from_name(const struct iio_dev *indio_dev, const char *name)
  89 {
  90         int i;
  91         const struct iio_chan_spec *chan = NULL;
  92
  93         for (i = 0; i < indio_dev->num_channels; i++)
  94                 if (indio_dev->channels[i].datasheet_name &&
  95                     strcmp(name, indio_dev->channels[i].datasheet_name) == 0) {
  96                         chan = &indio_dev->channels[i];
  97                         break;
  98                 }
  99         return chan;
 100 }
 101
 102 #ifdef CONFIG_OF
 103
 104 static int iio_dev_node_match(struct device *dev, const void *data)
 105 {
 106         return dev->of_node == data && dev->type == &iio_device_type;
 107 }
 108
 109 /**
 110  * __of_iio_simple_xlate - translate iiospec to the IIO channel index
 111  * @indio_dev:  pointer to the iio_dev structure
 112  * @iiospec:    IIO specifier as found in the device tree
 113  *
 114  * This is simple translation function, suitable for the most 1:1 mapped
 115  * channels in IIO chips. This function performs only one sanity check:
 116  * whether IIO index is less than num_channels (that is specified in the
 117  * iio_dev).
 118  */
 119 static int __of_iio_simple_xlate(struct iio_dev *indio_dev,
 120                                 const struct of_phandle_args *iiospec)
 121 {
 122         if (!iiospec->args_count)
 123                 return 0;
 124
 125         if (iiospec->args[0] >= indio_dev->num_channels) {
 126                 dev_err(&indio_dev->dev, "invalid channel index %u\n",
 127                         iiospec->args[0]);
 128                 return -EINVAL;
 129         }
 130
 131         return iiospec->args[0];
 132 }
 133
 134 static int __of_iio_channel_get(struct iio_channel *channel,
 135                                 struct device_node *np, int index)
 136 {
 137         struct device *idev;
 138         struct iio_dev *indio_dev;
 139         int err;
 140         struct of_phandle_args iiospec;
 141
 142         err = of_parse_phandle_with_args(np, "io-channels",
 143                                          "#io-channel-cells",
 144                                          index, &iiospec);
 145         if (err)
 146                 return err;
 147
 148         idev = bus_find_device(&iio_bus_type, NULL, iiospec.np,
 149                                iio_dev_node_match);
 150         of_node_put(iiospec.np);
 151         if (idev == NULL)
 152                 return -EPROBE_DEFER;
 153
 154         indio_dev = dev_to_iio_dev(idev);
 155         channel->indio_dev = indio_dev;
 156         if (indio_dev->info->of_xlate)
 157                 index = indio_dev->info->of_xlate(indio_dev, &iiospec);
 158         else
 159                 index = __of_iio_simple_xlate(indio_dev, &iiospec);
 160         if (index < 0)
 161                 goto err_put;
 162         channel->channel = &indio_dev->channels[index];
 163
 164         return 0;
 165
 166 err_put:
 167         iio_device_put(indio_dev);
 168         return index;
 169 }
 170
 171 static struct iio_channel *of_iio_channel_get(struct device_node *np, int index)
 172 {
 173         struct iio_channel *channel;
 174         int err;
 175
 176         if (index < 0)
 177                 return ERR_PTR(-EINVAL);
 178
 179         channel = kzalloc(sizeof(*channel), GFP_KERNEL);
 180         if (channel == NULL)
 181                 return ERR_PTR(-ENOMEM);
 182
 183         err = __of_iio_channel_get(channel, np, index);
 184         if (err)
 185                 goto err_free_channel;
 186
 187         return channel;
 188
 189 err_free_channel:
 190         kfree(channel);
 191         return ERR_PTR(err);
 192 }
 193
 194 struct iio_channel *of_iio_channel_get_by_name(struct device_node *np,
 195                                                const char *name)
 196 {
 197         struct iio_channel *chan = NULL;
 198
 199         /* Walk up the tree of devices looking for a matching iio channel */
 200         while (np) {
 201                 int index = 0;
 202
 203                 /*
 204                  * For named iio channels, first look up the name in the
 205                  * "io-channel-names" property.  If it cannot be found, the
 206                  * index will be an error code, and of_iio_channel_get()
 207                  * will fail.
 208                  */
 209                 if (name)
 210                         index = of_property_match_string(np, "io-channel-names",
 211                                                          name);
 212                 chan = of_iio_channel_get(np, index);
 213                 if (!IS_ERR(chan) || PTR_ERR(chan) == -EPROBE_DEFER)
 214                         break;
 215                 else if (name && index >= 0) {
 216                         pr_err("ERROR: could not get IIO channel %pOF:%s(%i)\n",
 217                                 np, name ? name : "", index);
 218                         return NULL;
 219                 }
 220
 221                 /*
 222                  * No matching IIO channel found on this node.
 223                  * If the parent node has a "io-channel-ranges" property,
 224                  * then we can try one of its channels.
 225                  */
 226                 np = np->parent;
 227                 if (np && !of_get_property(np, "io-channel-ranges", NULL))
 228                         return NULL;
 229         }
 230
 231         return chan;
 232 }
 233 EXPORT_SYMBOL_GPL(of_iio_channel_get_by_name);
 234
 235 static struct iio_channel *of_iio_channel_get_all(struct device *dev)
 236 {
 237         struct iio_channel *chans;
 238         int i, mapind, nummaps = 0;
 239         int ret;
 240
 241         do {
 242                 ret = of_parse_phandle_with_args(dev->of_node,
 243                                                  "io-channels",
 244                                                  "#io-channel-cells",
 245                                                  nummaps, NULL);
 246                 if (ret < 0)
 247                         break;
 248         } while (++nummaps);
 249
 250         if (nummaps == 0)       /* no error, return NULL to search map table */
 251                 return NULL;
 252
 253         /* NULL terminated array to save passing size */
 254         chans = kcalloc(nummaps + 1, sizeof(*chans), GFP_KERNEL);
 255         if (chans == NULL)
 256                 return ERR_PTR(-ENOMEM);
 257
 258         /* Search for OF matches */
 259         for (mapind = 0; mapind < nummaps; mapind++) {
 260                 ret = __of_iio_channel_get(&chans[mapind], dev->of_node,
 261                                            mapind);
 262                 if (ret)
 263                         goto error_free_chans;
 264         }
 265         return chans;
 266
 267 error_free_chans:
 268         for (i = 0; i < mapind; i++)
 269                 iio_device_put(chans[i].indio_dev);
 270         kfree(chans);
 271         return ERR_PTR(ret);
 272 }
 273
 274 #else /* CONFIG_OF */
 275
 276 static inline struct iio_channel *of_iio_channel_get_all(struct device *dev)
 277 {
 278         return NULL;
 279 }
 280
 281 #endif /* CONFIG_OF */
 282
 283 static struct iio_channel *iio_channel_get_sys(const char *name,
 284                                                const char *channel_name)
 285 {
 286         struct iio_map_internal *c_i = NULL, *c = NULL;
 287         struct iio_channel *channel;
 288         int err;
 289
 290         if (name == NULL && channel_name == NULL)
 291                 return ERR_PTR(-ENODEV);
 292
 293         /* first find matching entry the channel map */
 294         mutex_lock(&iio_map_list_lock);
 295         list_for_each_entry(c_i, &iio_map_list, l) {
 296                 if ((name && strcmp(name, c_i->map->consumer_dev_name) != 0) ||
 297                     (channel_name &&
 298                      strcmp(channel_name, c_i->map->consumer_channel) != 0))
 299                         continue;
 300                 c = c_i;
 301                 iio_device_get(c->indio_dev);
 302                 break;
 303         }
 304         mutex_unlock(&iio_map_list_lock);
 305         if (c == NULL)
 306                 return ERR_PTR(-ENODEV);
 307
 308         channel = kzalloc(sizeof(*channel), GFP_KERNEL);
 309         if (channel == NULL) {
 310                 err = -ENOMEM;
 311                 goto error_no_mem;
 312         }
 313
 314         channel->indio_dev = c->indio_dev;
 315
 316         if (c->map->adc_channel_label) {
 317                 channel->channel =
 318                         iio_chan_spec_from_name(channel->indio_dev,
 319                                                 c->map->adc_channel_label);
 320
 321                 if (channel->channel == NULL) {
 322                         err = -EINVAL;
 323                         goto error_no_chan;
 324                 }
 325         }
 326
 327         return channel;
 328
 329 error_no_chan:
 330         kfree(channel);
 331 error_no_mem:
 332         iio_device_put(c->indio_dev);
 333         return ERR_PTR(err);
 334 }
 335
 336 struct iio_channel *iio_channel_get(struct device *dev,
 337                                     const char *channel_name)
 338 {
 339         const char *name = dev ? dev_name(dev) : NULL;
 340         struct iio_channel *channel;
 341
 342         if (dev) {
 343                 channel = of_iio_channel_get_by_name(dev->of_node,
 344                                                      channel_name);
 345                 if (channel != NULL)
 346                         return channel;
 347         }
 348
 349         return iio_channel_get_sys(name, channel_name);
 350 }
 351 EXPORT_SYMBOL_GPL(iio_channel_get);
 352
 353 void iio_channel_release(struct iio_channel *channel)
 354 {
 355         if (!channel)
 356                 return;
 357         iio_device_put(channel->indio_dev);
 358         kfree(channel);
 359 }
 360 EXPORT_SYMBOL_GPL(iio_channel_release);
 361
 362 static void devm_iio_channel_free(struct device *dev, void *res)
 363 {
 364         struct iio_channel *channel = *(struct iio_channel **)res;
 365
 366         iio_channel_release(channel);
 367 }
 368
 369 struct iio_channel *devm_iio_channel_get(struct device *dev,
 370                                          const char *channel_name)
 371 {
 372         struct iio_channel **ptr, *channel;
 373
 374         ptr = devres_alloc(devm_iio_channel_free, sizeof(*ptr), GFP_KERNEL);
 375         if (!ptr)
 376                 return ERR_PTR(-ENOMEM);
 377
 378         channel = iio_channel_get(dev, channel_name);
 379         if (IS_ERR(channel)) {
 380                 devres_free(ptr);
 381                 return channel;
 382         }
 383
 384         *ptr = channel;
 385         devres_add(dev, ptr);
 386
 387         return channel;
 388 }
 389 EXPORT_SYMBOL_GPL(devm_iio_channel_get);
 390
 391 struct iio_channel *devm_of_iio_channel_get_by_name(struct device *dev,
 392                                                     struct device_node *np,
 393                                                     const char *channel_name)
 394 {
 395         struct iio_channel **ptr, *channel;
 396
 397         ptr = devres_alloc(devm_iio_channel_free, sizeof(*ptr), GFP_KERNEL);
 398         if (!ptr)
 399                 return ERR_PTR(-ENOMEM);
 400
 401         channel = of_iio_channel_get_by_name(np, channel_name);
 402         if (IS_ERR(channel)) {
 403                 devres_free(ptr);
 404                 return channel;
 405         }
 406
 407         *ptr = channel;
 408         devres_add(dev, ptr);
 409
 410         return channel;
 411 }
 412 EXPORT_SYMBOL_GPL(devm_of_iio_channel_get_by_name);
 413
 414 struct iio_channel *iio_channel_get_all(struct device *dev)
 415 {
 416         const char *name;
 417         struct iio_channel *chans;
 418         struct iio_map_internal *c = NULL;
 419         int nummaps = 0;
 420         int mapind = 0;
 421         int i, ret;
 422
 423         if (dev == NULL)
 424                 return ERR_PTR(-EINVAL);
 425
 426         chans = of_iio_channel_get_all(dev);
 427         if (chans)
 428                 return chans;
 429
 430         name = dev_name(dev);
 431
 432         mutex_lock(&iio_map_list_lock);
 433         /* first count the matching maps */
 434         list_for_each_entry(c, &iio_map_list, l)
 435                 if (name && strcmp(name, c->map->consumer_dev_name) != 0)
 436                         continue;
 437                 else
 438                         nummaps++;
 439
 440         if (nummaps == 0) {
 441                 ret = -ENODEV;
 442                 goto error_ret;
 443         }
 444
 445         /* NULL terminated array to save passing size */
 446         chans = kcalloc(nummaps + 1, sizeof(*chans), GFP_KERNEL);
 447         if (chans == NULL) {
 448                 ret = -ENOMEM;
 449                 goto error_ret;
 450         }
 451
 452         /* for each map fill in the chans element */
 453         list_for_each_entry(c, &iio_map_list, l) {
 454                 if (name && strcmp(name, c->map->consumer_dev_name) != 0)
 455                         continue;
 456                 chans[mapind].indio_dev = c->indio_dev;
 457                 chans[mapind].data = c->map->consumer_data;
 458                 chans[mapind].channel =
 459                         iio_chan_spec_from_name(chans[mapind].indio_dev,
 460                                                 c->map->adc_channel_label);
 461                 if (chans[mapind].channel == NULL) {
 462                         ret = -EINVAL;
 463                         goto error_free_chans;
 464                 }
 465                 iio_device_get(chans[mapind].indio_dev);
 466                 mapind++;
 467         }
 468         if (mapind == 0) {
 469                 ret = -ENODEV;
 470                 goto error_free_chans;
 471         }
 472         mutex_unlock(&iio_map_list_lock);
 473
 474         return chans;
 475
 476 error_free_chans:
 477         for (i = 0; i < nummaps; i++)
 478                 iio_device_put(chans[i].indio_dev);
 479         kfree(chans);
 480 error_ret:
 481         mutex_unlock(&iio_map_list_lock);
 482
 483         return ERR_PTR(ret);
 484 }
 485 EXPORT_SYMBOL_GPL(iio_channel_get_all);
 486
 487 void iio_channel_release_all(struct iio_channel *channels)
 488 {
 489         struct iio_channel *chan = &channels[0];
 490
 491         while (chan->indio_dev) {
 492                 iio_device_put(chan->indio_dev);
 493                 chan++;
 494         }
 495         kfree(channels);
 496 }
 497 EXPORT_SYMBOL_GPL(iio_channel_release_all);
 498
 499 static void devm_iio_channel_free_all(struct device *dev, void *res)
 500 {
 501         struct iio_channel *channels = *(struct iio_channel **)res;
 502
 503         iio_channel_release_all(channels);
 504 }
 505
 506 struct iio_channel *devm_iio_channel_get_all(struct device *dev)
 507 {
 508         struct iio_channel **ptr, *channels;
 509
 510         ptr = devres_alloc(devm_iio_channel_free_all, sizeof(*ptr), GFP_KERNEL);
 511         if (!ptr)
 512                 return ERR_PTR(-ENOMEM);
 513
 514         channels = iio_channel_get_all(dev);
 515         if (IS_ERR(channels)) {
 516                 devres_free(ptr);
 517                 return channels;
 518         }
 519
 520         *ptr = channels;
 521         devres_add(dev, ptr);
 522
 523         return channels;
 524 }
 525 EXPORT_SYMBOL_GPL(devm_iio_channel_get_all);
 526
 527 static int iio_channel_read(struct iio_channel *chan, int *val, int *val2,
 528         enum iio_chan_info_enum info)
 529 {
 530         int unused;
 531         int vals[INDIO_MAX_RAW_ELEMENTS];
 532         int ret;
 533         int val_len = 2;
 534
 535         if (val2 == NULL)
 536                 val2 = &unused;
 537
 538         if (!iio_channel_has_info(chan->channel, info))
 539                 return -EINVAL;
 540
 541         if (chan->indio_dev->info->read_raw_multi) {
 542                 ret = chan->indio_dev->info->read_raw_multi(chan->indio_dev,
 543                                         chan->channel, INDIO_MAX_RAW_ELEMENTS,
 544                                         vals, &val_len, info);
 545                 *val = vals[0];
 546                 *val2 = vals[1];
 547         } else
 548                 ret = chan->indio_dev->info->read_raw(chan->indio_dev,
 549                                         chan->channel, val, val2, info);
 550
 551         return ret;
 552 }
 553
 554 int iio_read_channel_raw(struct iio_channel *chan, int *val)
 555 {
 556         int ret;
 557
 558         mutex_lock(&chan->indio_dev->info_exist_lock);
 559         if (chan->indio_dev->info == NULL) {
 560                 ret = -ENODEV;
 561                 goto err_unlock;
 562         }
 563
 564         ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_RAW);
 565 err_unlock:
 566         mutex_unlock(&chan->indio_dev->info_exist_lock);
 567
 568         return ret;
 569 }
 570 EXPORT_SYMBOL_GPL(iio_read_channel_raw);
 571
 572 int iio_read_channel_average_raw(struct iio_channel *chan, int *val)
 573 {
 574         int ret;
 575
 576         mutex_lock(&chan->indio_dev->info_exist_lock);
 577         if (chan->indio_dev->info == NULL) {
 578                 ret = -ENODEV;
 579                 goto err_unlock;
 580         }
 581
 582         ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_AVERAGE_RAW);
 583 err_unlock:
 584         mutex_unlock(&chan->indio_dev->info_exist_lock);
 585
 586         return ret;
 587 }
 588 EXPORT_SYMBOL_GPL(iio_read_channel_average_raw);
 589
 590 static int iio_convert_raw_to_processed_unlocked(struct iio_channel *chan,
 591         int raw, int *processed, unsigned int scale)
 592 {
 593         int scale_type, scale_val, scale_val2, offset;
 594         s64 raw64 = raw;
 595         int ret;
 596
 597         ret = iio_channel_read(chan, &offset, NULL, IIO_CHAN_INFO_OFFSET);
 598         if (ret >= 0)
 599                 raw64 += offset;
 600
 601         scale_type = iio_channel_read(chan, &scale_val, &scale_val2,
 602                                         IIO_CHAN_INFO_SCALE);
 603         if (scale_type < 0) {
 604                 /*
 605                  * Just pass raw values as processed if no scaling is
 606                  * available.
 607                  */
 608                 *processed = raw;
 609                 return 0;
 610         }
 611
 612         switch (scale_type) {
 613         case IIO_VAL_INT:
 614                 *processed = raw64 * scale_val;
 615                 break;
 616         case IIO_VAL_INT_PLUS_MICRO:
 617                 if (scale_val2 < 0)
 618                         *processed = -raw64 * scale_val;
 619                 else
 620                         *processed = raw64 * scale_val;
 621                 *processed += div_s64(raw64 * (s64)scale_val2 * scale,
 622                                       1000000LL);
 623                 break;
 624         case IIO_VAL_INT_PLUS_NANO:
 625                 if (scale_val2 < 0)
 626                         *processed = -raw64 * scale_val;
 627                 else
 628                         *processed = raw64 * scale_val;
 629                 *processed += div_s64(raw64 * (s64)scale_val2 * scale,
 630                                       1000000000LL);
 631                 break;
 632         case IIO_VAL_FRACTIONAL:
 633                 *processed = div_s64(raw64 * (s64)scale_val * scale,
 634                                      scale_val2);
 635                 break;
 636         case IIO_VAL_FRACTIONAL_LOG2:
 637                 *processed = (raw64 * (s64)scale_val * scale) >> scale_val2;
 638                 break;
 639         default:
 640                 return -EINVAL;
 641         }
 642
 643         return 0;
 644 }
 645
 646 int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
 647         int *processed, unsigned int scale)
 648 {
 649         int ret;
 650
 651         mutex_lock(&chan->indio_dev->info_exist_lock);
 652         if (chan->indio_dev->info == NULL) {
 653                 ret = -ENODEV;
 654                 goto err_unlock;
 655         }
 656
 657         ret = iio_convert_raw_to_processed_unlocked(chan, raw, processed,
 658                                                         scale);
 659 err_unlock:
 660         mutex_unlock(&chan->indio_dev->info_exist_lock);
 661
 662         return ret;
 663 }
 664 EXPORT_SYMBOL_GPL(iio_convert_raw_to_processed);
 665
 666 int iio_read_channel_attribute(struct iio_channel *chan, int *val, int *val2,
 667                                enum iio_chan_info_enum attribute)
 668 {
 669         int ret;
 670
 671         mutex_lock(&chan->indio_dev->info_exist_lock);
 672         if (chan->indio_dev->info == NULL) {
 673                 ret = -ENODEV;
 674                 goto err_unlock;
 675         }
 676
 677         ret = iio_channel_read(chan, val, val2, attribute);
 678 err_unlock:
 679         mutex_unlock(&chan->indio_dev->info_exist_lock);
 680
 681         return ret;
 682 }
 683 EXPORT_SYMBOL_GPL(iio_read_channel_attribute);
 684
 685 int iio_read_channel_offset(struct iio_channel *chan, int *val, int *val2)
 686 {
 687         return iio_read_channel_attribute(chan, val, val2, IIO_CHAN_INFO_OFFSET);
 688 }
 689 EXPORT_SYMBOL_GPL(iio_read_channel_offset);
 690
 691 int iio_read_channel_processed(struct iio_channel *chan, int *val)
 692 {
 693         int ret;
 694
 695         mutex_lock(&chan->indio_dev->info_exist_lock);
 696         if (chan->indio_dev->info == NULL) {
 697                 ret = -ENODEV;
 698                 goto err_unlock;
 699         }
 700
 701         if (iio_channel_has_info(chan->channel, IIO_CHAN_INFO_PROCESSED)) {
 702                 ret = iio_channel_read(chan, val, NULL,
 703                                        IIO_CHAN_INFO_PROCESSED);
 704         } else {
 705                 ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_RAW);
 706                 if (ret < 0)
 707                         goto err_unlock;
 708                 ret = iio_convert_raw_to_processed_unlocked(chan, *val, val, 1);
 709         }
 710
 711 err_unlock:
 712         mutex_unlock(&chan->indio_dev->info_exist_lock);
 713
 714         return ret;
 715 }
 716 EXPORT_SYMBOL_GPL(iio_read_channel_processed);
 717
 718 int iio_read_channel_scale(struct iio_channel *chan, int *val, int *val2)
 719 {
 720         return iio_read_channel_attribute(chan, val, val2, IIO_CHAN_INFO_SCALE);
 721 }
 722 EXPORT_SYMBOL_GPL(iio_read_channel_scale);
 723
 724 static int iio_channel_read_avail(struct iio_channel *chan,
 725                                   const int **vals, int *type, int *length,
 726                                   enum iio_chan_info_enum info)
 727 {
 728         if (!iio_channel_has_available(chan->channel, info))
 729                 return -EINVAL;
 730
 731         return chan->indio_dev->info->read_avail(chan->indio_dev, chan->channel,
 732                                                  vals, type, length, info);
 733 }
 734
 735 int iio_read_avail_channel_attribute(struct iio_channel *chan,
 736                                      const int **vals, int *type, int *length,
 737                                      enum iio_chan_info_enum attribute)
 738 {
 739         int ret;
 740
 741         mutex_lock(&chan->indio_dev->info_exist_lock);
 742         if (!chan->indio_dev->info) {
 743                 ret = -ENODEV;
 744                 goto err_unlock;
 745         }
 746
 747         ret = iio_channel_read_avail(chan, vals, type, length, attribute);
 748 err_unlock:
 749         mutex_unlock(&chan->indio_dev->info_exist_lock);
 750
 751         return ret;
 752 }
 753 EXPORT_SYMBOL_GPL(iio_read_avail_channel_attribute);
 754
 755 int iio_read_avail_channel_raw(struct iio_channel *chan,
 756                                const int **vals, int *length)
 757 {
 758         int ret;
 759         int type;
 760
 761         ret = iio_read_avail_channel_attribute(chan, vals, &type, length,
 762                                          IIO_CHAN_INFO_RAW);
 763
 764         if (ret >= 0 && type != IIO_VAL_INT)
 765                 /* raw values are assumed to be IIO_VAL_INT */
 766                 ret = -EINVAL;
 767
 768         return ret;
 769 }
 770 EXPORT_SYMBOL_GPL(iio_read_avail_channel_raw);
 771
 772 static int iio_channel_read_max(struct iio_channel *chan,
 773                                 int *val, int *val2, int *type,
 774                                 enum iio_chan_info_enum info)
 775 {
 776         int unused;
 777         const int *vals;
 778         int length;
 779         int ret;
 780
 781         if (!val2)
 782                 val2 = &unused;
 783
 784         ret = iio_channel_read_avail(chan, &vals, type, &length, info);
 785         switch (ret) {
 786         case IIO_AVAIL_RANGE:
 787                 switch (*type) {
 788                 case IIO_VAL_INT:
 789                         *val = vals[2];
 790                         break;
 791                 default:
 792                         *val = vals[4];
 793                         *val2 = vals[5];
 794                 }
 795                 return 0;
 796
 797         case IIO_AVAIL_LIST:
 798                 if (length <= 0)
 799                         return -EINVAL;
 800                 switch (*type) {
 801                 case IIO_VAL_INT:
 802                         *val = vals[--length];
 803                         while (length) {
 804                                 if (vals[--length] > *val)
 805                                         *val = vals[length];
 806                         }
 807                         break;
 808                 default:
 809                         /* FIXME: learn about max for other iio values */
 810                         return -EINVAL;
 811                 }
 812                 return 0;
 813
 814         default:
 815                 return ret;
 816         }
 817 }
 818
 819 int iio_read_max_channel_raw(struct iio_channel *chan, int *val)
 820 {
 821         int ret;
 822         int type;
 823
 824         mutex_lock(&chan->indio_dev->info_exist_lock);
 825         if (!chan->indio_dev->info) {
 826                 ret = -ENODEV;
 827                 goto err_unlock;
 828         }
 829
 830         ret = iio_channel_read_max(chan, val, NULL, &type, IIO_CHAN_INFO_RAW);
 831 err_unlock:
 832         mutex_unlock(&chan->indio_dev->info_exist_lock);
 833
 834         return ret;
 835 }
 836 EXPORT_SYMBOL_GPL(iio_read_max_channel_raw);
 837
 838 int iio_get_channel_type(struct iio_channel *chan, enum iio_chan_type *type)
 839 {
 840         int ret = 0;
 841         /* Need to verify underlying driver has not gone away */
 842
 843         mutex_lock(&chan->indio_dev->info_exist_lock);
 844         if (chan->indio_dev->info == NULL) {
 845                 ret = -ENODEV;
 846                 goto err_unlock;
 847         }
 848
 849         *type = chan->channel->type;
 850 err_unlock:
 851         mutex_unlock(&chan->indio_dev->info_exist_lock);
 852
 853         return ret;
 854 }
 855 EXPORT_SYMBOL_GPL(iio_get_channel_type);
 856
 857 static int iio_channel_write(struct iio_channel *chan, int val, int val2,
 858                              enum iio_chan_info_enum info)
 859 {
 860         return chan->indio_dev->info->write_raw(chan->indio_dev,
 861                                                 chan->channel, val, val2, info);
 862 }
 863
 864 int iio_write_channel_attribute(struct iio_channel *chan, int val, int val2,
 865                                 enum iio_chan_info_enum attribute)
 866 {
 867         int ret;
 868
 869         mutex_lock(&chan->indio_dev->info_exist_lock);
 870         if (chan->indio_dev->info == NULL) {
 871                 ret = -ENODEV;
 872                 goto err_unlock;
 873         }
 874
 875         ret = iio_channel_write(chan, val, val2, attribute);
 876 err_unlock:
 877         mutex_unlock(&chan->indio_dev->info_exist_lock);
 878
 879         return ret;
 880 }
 881 EXPORT_SYMBOL_GPL(iio_write_channel_attribute);
 882
 883 int iio_write_channel_raw(struct iio_channel *chan, int val)
 884 {
 885         return iio_write_channel_attribute(chan, val, 0, IIO_CHAN_INFO_RAW);
 886 }
 887 EXPORT_SYMBOL_GPL(iio_write_channel_raw);
 888
 889 unsigned int iio_get_channel_ext_info_count(struct iio_channel *chan)
 890 {
 891         const struct iio_chan_spec_ext_info *ext_info;
 892         unsigned int i = 0;
 893
 894         if (!chan->channel->ext_info)
 895                 return i;
 896
 897         for (ext_info = chan->channel->ext_info; ext_info->name; ext_info++)
 898                 ++i;
 899
 900         return i;
 901 }
 902 EXPORT_SYMBOL_GPL(iio_get_channel_ext_info_count);
 903
 904 static const struct iio_chan_spec_ext_info *iio_lookup_ext_info(
 905                                                 const struct iio_channel *chan,
 906                                                 const char *attr)
 907 {
 908         const struct iio_chan_spec_ext_info *ext_info;
 909
 910         if (!chan->channel->ext_info)
 911                 return NULL;
 912
 913         for (ext_info = chan->channel->ext_info; ext_info->name; ++ext_info) {
 914                 if (!strcmp(attr, ext_info->name))
 915                         return ext_info;
 916         }
 917
 918         return NULL;
 919 }
 920
 921 ssize_t iio_read_channel_ext_info(struct iio_channel *chan,
 922                                   const char *attr, char *buf)
 923 {
 924         const struct iio_chan_spec_ext_info *ext_info;
 925
 926         ext_info = iio_lookup_ext_info(chan, attr);
 927         if (!ext_info)
 928                 return -EINVAL;
 929
 930         return ext_info->read(chan->indio_dev, ext_info->private,
 931                               chan->channel, buf);
 932 }
 933 EXPORT_SYMBOL_GPL(iio_read_channel_ext_info);
 934
 935 ssize_t iio_write_channel_ext_info(struct iio_channel *chan, const char *attr,
 936                                    const char *buf, size_t len)
 937 {
 938         const struct iio_chan_spec_ext_info *ext_info;
 939
 940         ext_info = iio_lookup_ext_info(chan, attr);
 941         if (!ext_info)
 942                 return -EINVAL;
 943
 944         return ext_info->write(chan->indio_dev, ext_info->private,
 945                                chan->channel, buf, len);
 946 }
 947 EXPORT_SYMBOL_GPL(iio_write_channel_ext_info);